The need for efficient and effective tools for the installation of building materials such as drywall, the need for rapidly and sequentially feeding fastening devices from a supply to such tools, and the need for properly recessing the fasteners in the surface of the building materials, have been discussed in my issued U.S. Pat. No. 4,778,094 entitled NAIL AND DIMPLER DRIVING APPARATUS FOR NAILING GUN, hereby expressly incorporated herein by reference. In that patent, I taught the securing of material such as drywall with fasteners such as drywall nails with a sequentially fed gun which provides dimpling capabilities for recessing the heads of the fastening devices. Sequentially fed fastening devices such as nailing guns are commonly referred to in the industry as "collated" fastener guns.
The construction industry, particularly in the United States, has exhibited an increased desire for securing building materials to one another by utilizing the holding power of screws, or fastening devices which are inserted into the materials with a rotational motion, to materials, as for example, sheet materials such drywall, to framing and other members in building construction. Screws usually are best installed by imparting a forward driving force or motion against a screw head at one end of the screw to thrust a point at the other end of the screw into the materials being fastened. Coupled with this forward force or motion is a rotational force or motion which cooperates with a helical thread on the screw to drive the screw into the materials and to draw and hold the materials together. The fastening and holding function of screws so driven is generally regarded in the construction industry as superior to the fastening and holding function performed by impact or impulse driven fasteners such as nails or staples. In addition, the head depth of a fastener, or the recessing into the material of the head of the fastener, which is important in installing drywall and other building materials, can be more precisely controlled with a threaded screw than with the impact or impulse driven fastener.
In the prior art, the installation of screws had, for many years, been performed by hand with the use of conventional screwdrivers. This slow, labor intensive process rendered the use of screws in building construction, particularly for installation of drywall and other sheet materials, too time consuming and expensive to be practical. The practical use of screws for such purposes in building construction has been enhanced by the development of power driven screwdrivers. In the use of such screwdrivers in building construction, supplying the screws to be driven by the power tool has, for the most part at least, been done by hand by the operator or user of the tool.
Efficient and effective high speed devices for automatically supplying screws to power screwdrivers, that is, power screwdrivers with collated screw feeds, have not existed in the prior art. Thus, while the development of power screwdrivers has facilitated the practical use of screws in some phases of building construction, such tools have not been sufficiently effective to provide reliable high speed use of screws so as to render their use in the installation of materials such as drywall as economical as is desired.
Furthermore, there is and will continue to be a need in the building construction industry to insert, tighten, or remove individual screws in the performance of a wide variety of small or miscellaneous tasks. The availability of power screwdrivers for such purposes will continue to be an important requirement, since any installation of almost any screw by hand is an unduly slow and tiring process.
Furthermore, when screws are installed with power screw drivers, upon installation, they frequently require additional tightening and adjustment. Accordingly, there and will continue to be a constant need to have readily on hand at a construction site a power screwdriver which is capable of driving screws which are already set in the material to, for example, remove or tighten such screws, or to drive individual screws which may be supplied in varying sizes by the manual selection of the construction worker.
Accordingly, there is a need to provide a power driven screwdriver which is efficient and effective to satisfy the needs of the construction industry, particularly in fastening materials such as drywall to structural members in building construction.